This invention relates to the field of photovoltaic conversion.
Electricity generators comprising photovoltaic cells are known in the state of the art. These cells are composed of semi-conducting barriers that output an electric signal that depends on the light intensity illuminating their surface. Various works have been done to improve the efficiency of this type of cell.
A first series of work applies to improvements to the cells themselves, for example, by the production of monocrystalline cells. These improvements result in cells with an extremely high manufacturing cost.
Another series of work has been done to improve cell illumination conditions, particularly by techniques to convert the solar spectrum to optimally adapt light radiation acting on the cells, to the sensitivity curve of these cells.
For example, U.S. Pat. NO. 4,110,123 discloses an example photovoltaic conversion device comprising a support doped with fluorescent materials.
U.S. Pat. No. 5,813,238 also discloses a solar sensor presenting durable fluorescent properties comprising a polymer matrix, a coloring agent and a stabilizer. The polymer matrix is composed of polycarbonate and the coloring agent is chosen among the group comprising essentially thioxanthobe, perylene imide and/or compounds of thioindigoid. This patent also proposes to position reflecting elements such that collected sunlight can be aimed at a solar cell.
U.S. Pat. No. 4,367,367 describes a collector suitable for concentrating solar energy on a photoelectric cell comprising at least one fluorescent doping agent. The cell is fixed on one edge of the collector which is coated with a reflecting coating.
U.S. Pat. No. 4,395,582 also describes a solar converter comprising a substrate doped with photo-active combinations called xe2x80x9clight cascadesxe2x80x9d to improve the quality of the light spectrum illuminating the photoelectric cells.
Accordingly, it would be advantageous to provide an improved, compact, high efficiency photovoltaic generator.
This invention relates to a photovoltaic generator including at least one photovoltaic cell, and a transparent matrix placed with at least one optically active material with an absorption wavelength xcexa and a reemission wavelength xcexr, the optically active material selected such that xcexa corresponds to a range of the photovoltaic cell with a lower sensitivity than xcexr, the matrix having an input surface and an opposite surface and comprises a reflecting coating and a dichroic filter on the input surface that substantially reflects wavelengths longer than about 950 nm and is substantially transparent for wavelengths less than about 950 nm, and on the opposite surface the matrix has a reflecting coating that reflects wavelengths greater than about 400 nm, and wherein the photovoltaic cell is included in the matrix.